Vacuum seal for driers



Aug. 29, 1933. A. N. RUSSELL 1,924,883

VACUUM SEAL FOR DRIERS Filed- April 24, '1931 5 Sheets-Sheet 1 g n/ 4 5- 90 5 47 ////y/ EICII 0 INVENTGB ANDREWMRUSSELL ATTORNEY Aug. 29, 1933. S L VACUUM SEAL FOR DRIERS Filed April 24, 1931 5 Sheets-Sheet 2 FIG. E E164 INVEN TOR ANDREW.N.RUSSELL ATTORNE Y Aug. 29, 1933.

A. N. RUSSELL VACUUM SEAL FOR DRIERS Filed April 24, 1951 Y/ IV/ 5 Sheets-Sheet 3 Ila INVENTOR ANDREWNRUSSELL BY WW ATTORNEY Aug. 2-9, 1933. A. N. RUSSELL 1,924,883

VACUUM SEAL FOR DRIERS Filed April 24, 1931 5 Sheets-Sheet 4 INVENTOR ANDREW.N.RUSSELL Q BY AT TURN E Y 29, 1933. A. N. RUSSELL 1,924,883

VACUUM SEAL FOR DRIERS Filed April 24, 19 l 5 Sheets-Sheet 5 49 11a l 1?; FIG 6 4E 45 N NTOR ATTORNEY Patented Aug. 29, 1933 VACUUM SEAL roe DRIERS Andrew N. Russell, Montreal, Quebec, Canada,

assignor to Dominion Engineering Works Limited, Lachine, Canada Application April 24, 1931. Serial No. 532,493 14 Claims. (01. 34-48) This invention relates to sealing devices designed to permit a sheet of paper, pulp or other material to pass into or out of a vacuum chamber while preventing any substantial leakage of air into the interior of the chamber. More particularly, the present invention is chiefly concerned with the provision of an improved seal of the labyrinth type described in the application of Bernard A. Malkin, Serial No. 436,806

filed Mar. 18, 1930.

As herein described the present invention is applied to a vacuum chamber equipped with a main roll and a riding roll between which the sheet material is passed during its travel into or out of the vacuum chamber. A labyrinthian sealing member is associated with each roll and functions, as described in the Malkin application, to retard leakage of air across the face of the roll and into the interior of the vacuum chamber.

As applied to a vacuum chamber of this type the particular object of the present invention is to provide means whereby the riding roll is permitted to have all necessary movements and adjustments relative to the main roll without disturbing the adjustment or operative relation between the riding roll and its associated seal.

Another object is to provide novel means for mounting the riding roll and its associated labyrinth seal for unitary movement, said means ineluding pressure applying devices for holding the riding roll to the main roll and for resisting displacement of the riding roll by atmospheric pressure when a high vacuum is developed in the r vacuum chamber.

Another object is to provide means whereby the pressure applied to hold the riding roll to the main roll is controlled by the degree of vacuum developed in the vacuum chamber, this control being effected in such a Way that the creation of a high vacuum in the chamber which normally tends to promote lifting of the riding roll by atmospheric pressure is utilized to de velop counter pressure sufficient to overcome this lifting tendency of the riding roll.

Another object is to provide improved means for independently supporting the labyrinth seal members associated with the two rolls, said means including provision for independently adjusting the position of each seal member with respect to the opposing surface of the roll associated therewith. I

Another object is to provide improved end seals for retarding leakage of air between the ends the rolls and the adjacent walls of the vacuum chamber.

Theforegoing and other objects, as well as the advantages and characteristic features of the invention, will be more readily understood from the following detailed discussion taken in connection with the accompanying drawings, in C Fig. 1 is a fragmentary sideview of one endof a vacuum chamber equipped with sealing. devices constructed in accordance with this invention. In this view one side wall of the vacuum chamber is broken away at X to disclose the interior arrangement of the rolls and seals.

Fig. 2 is a sectional view taken substantiallyalong the line 22 of Fig. 1.

Fig. 3 is a sectional view taken substantially along the line 33 of Fig. 1.

Fig. 4. is a fragmentary end view of the assembly shown in Fig. 1.

Fig. 5 is an enlarged fragmentary side view of the vacuum chamber showing the external appearance of the end seal assembly associated with each roll.

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 5.v r I Fig. '7 is a sectional view taken along the line 77 of Fig. 5. 1

Fig. 8 is a sectional view taken alongthe line 8--8 of Fig. 7. j H i Fig. 9 is a fragmentary view of ade'tail.

Referring more particularly to the drawings, (11) designates a vacuum drying chamber equipped with the usual drying cylinders (12), drier felts (13), and felt guide rolls (14). Only one end of the vacuum chamber is shown in the present instance and it is to be understood that this may be taken to represent either the. en-

trance or the exit end since the invention is equally applicable to both. The sheet of paper or other material to be dried is indicated at (15) and passes into or out of the vacuum chamber (11) between the main roll (16) and a riding roll (17).. The main roll (16)is made'wholly of metal and is carried in stationary bearings (18) mounted in side walls (11a) of .thevacuum chamber. The riding roll (1'?) is provided with 9 a rubber covering (17a) and is'carriedin bearings (19) mounted in a pair of swinging arms (20). These arms (20) are disposed outwardly of the side walls (11a) and are supported for swinging movement as hereinafter described. The tworolls are normally held in contact with each other throughout their length and the resiliency of the rubber covering (17a) serves to maintain this contact between the portions of the rolls lying beyond the side edges of the sheet (15) when said sheet is passing between the rolls.

Inward leakage of air across the faces of the rolls (16) and (1'7) is reduced to a minimum by the provision of the labyrinth seal members or boxes appearing at (21) and (22). These labyrinth seal members extend between the side walls (11a) of the vacuum chamber in close proximity to the exposed surfaces of the rolls (16) and (1'7), as shown to advantage in Fig. 1. Each seal member is provided in its roll opposing surface with a series of parallel longitudinal grooves (23). These grooves are formed and spaced apart to provide a'labyrinthian passage extending circumferentially around the roll between the roll surface and the opposing surface of the seal member. Malkin application previously referred to, the labyrinthian passage which is thus formed serves, in a well known manner, to retard to a maximum degree the inflow of air between the roll and the seal member. This retarding of air leakage into the vacuum chamber may also be considerably increased by making the inner groove of each series such, for example, as the inner groove designated (a) of relatively large size and connecting same to an auxiliary vacuum pump (not shown).. In this way a part or all of the air which leaks past the outer grooves of each series is extracted by the pump as it reaches the inner with side bars (24) and (25) which are adjustable to compensate for slight variations in the diameter of the roll (17) due to wear or regrinding of the rubber covering (17a). These bars may be secured in adjusted position by bolts (26) or by means of any other suitable securing means.

The labyrinth'seal members 21) and (22) are slidably associated with suitable supporting castings (2'7) and (28). Each seal member is ads justable with reference to the opposing roll surface by means of the adjusting bolts (29) These bolts are mounted in the web portions (30) and (31) of the castings (2'7) and (28) and are threadedly engaged with the seal members (21) and (22) as shown to advantage in Fig. 1. The seal member (21) is held to its supporting casting (27) by retaining bolts (32) which are fixed to the casting and pass through suitable slots (33) provided in the seal member. The seal member (22) is held in a similar manner to its supporting casting (28) by retaining bolts (34) fixed to the seal .member (22) and passing through slots (35) in the casting.

Suitable end seals are provided to retard air leakage between the ends of the rolls and the (39) and serves to prevent leakage around the inner portion of the bronze ring 40) while permitting longitudinal expansion of the rolls. A second rubber ring (43) is arranged for a similar purpose within the opening (41) at the outer end of the ring (40). In order to hold the sealing faces of the several sealing rings in close con- As explained more particularly in the tact with one another inward pressure is applied to the rubber ring (43) in the following manner. As shown to advantage in 5 to 9 inclusive, an inner pressure applying ring (44) is arranged to bear against the outer side of the rubber ring (43) and is free to move inwardly in response to the pressure exerted thereon by a plurality of bowed springs (45). These springs are arranged as shown in the drawings and have their intermediate portions secured to an outer pressure applying ring (48) which is slidably and rotatably mounted in the opening (41). A ring gear (4'7) is fixed to the pressure applying ring (46) and meshes with a plurality of axially movable pinions (48) having threaded engagement with studs (49) carried by the side wall (11a). Each pinion (48) is provided with shroud flanges (58) which fit upon opposite sides of the ring gear (4'7) so that the pinions and the gear, when rotated, are caused to be moved axially by reason of the threaded connection between the pinions and the studs (49). As shown more particularly in Fig. '7, one of the pinions (48) is adapted to serve as a drive pinion and to this end is provided with an hexagonal extension ('51) adapted to be engaged by a spanner to effect rotation of the pinion. As will be obvious from inspection of the drawings, the rotation of the drive pinion causes corresponding motion to be imparted to the remaining pinions through the ring gear (4'7) and the resulting axial movement of the pinions and ring gear along the length of the studs (49) serves to regulate the effective pressure of the springs (45) on the inner pressure applying ring (44).

With the exception of the drive pinion the seal at each end'or the main roll (16) is the same as that described in connection with the riding roll (1'7) and, therefore, has its component elements designated by the same reference characters. The only material difference between the end seals of the two rolls is that in the case of the main roll (16) the drive pinion designated (48a) is held against longitudinal movement between its bearings (53) and (54) and is provided with an elongated operating spindle (55) terminating in a hexagonal spanner engaging por-' tion (56). The length of the pinion (48a) is such that it maintains its driving engagement with the ring gear (4'?) when the latter is moved axially by the flanged pinions (48) travelling on the studs (49). As will be readily understood either of the two slightly different forms of drive pinions described herein may, if desired, be used to the exclusion of the other.

The casting (28), which supports the upper labyrinth seal member (22) is provided with integral trunnions (58). These trunnions are mounted to rotate in suitable bearing openings formed in the side walls (11a) and constitute horizontal pivots about which the casting (28) is movable. The trunnions (58) project outwardly beyond the walls (11a) and serve to carry the lower ends of the swinging arms (20) which are fixed to the trunnions in any suitable manner. It will thus be seen that the riding roll (17), labyrinth seal member 22, and casting (28) are mounted to move as a unit about the pivotal axis afforded by the trunnions (58) without disturbing their relative relation.

As shown in Fig. 1, each side wall (11a) carries a bracket (60) through which is threaded a jack screw (61) These screws are positioned beneath the upper or free ends of the arms (20) and pro vide means for swinging said arms upwardly to raise the riding roll (1'7) and thereby relieve the pressure on the rubber covering (17a) when the riding roll is not in use.

W hen there is a relatively high vacuum in the chamber (11), the atmospheric pressure on the riding roll (17) sometimes exceeds the weight of the roll and its fittings and tends to lift the ridin roll out of contact with the main roll (16). In order to overcome this and to maintain the rolls in proper engagement I provide a pressure applying means associated with each swinging arm (20) In each instance the pressure applying means includes a lever (63) having one end connected by a link (64) to a piston (65) operating in a cylinder (67). The cylinder (67) located externally of the vacuum chamber and has its outer end open to the atmosphere. The inner end of the cylinder (67) communicates with the interior of the vacuum chamber through a port (68) so that atmospheric pressure acting on the outer face of the piston is effective to move the piston towards the inner end of the cylinder. The degree of movement thus departed to the piston is dependent upon the degr e of vacuum created in the vacuum chamber. The remaining end of lever (63) is provided with a slot (69) containing a slide (79) which may be adjusted to various points along the length of the slot by the adjusting screw (71). This slide is pivotally supported by the trunnions (72) between the upper ends of a pair of links (73). (Only one of these links is shown in the drawings.) The lower ends of the links ('73) are mounted to swing about the fixed pivot (74) which is carried in a suitable manner by the side wall (11a). At a point adjacent the inner end of the slot (69) the lever (63) carries a pair of links (75) having their lower ends pivoted to opposite sides of the lever as indicated at (76). Extensions (77) are formed integral with the lower ends or" the links ('76) and carry between them a pivotally connected shoe (78) which is disposed to reciprocate in a suitable guide (79) A pressure plate (so) is pivotally connected to the upper ends of the links (75) as indicated at (81) and is provided at its extremities with suitable guide openings slidably receiving the guide pins (82) fixed to the inner portion of the arm (20) which passes between the links (75). Coil springs (83) surround the pins 82) and are confined between the pressure plate and the arm (20).

The movement of the piston (65) towards the inner end of the cylinder 67 in response to a high vacuum in the chamber (11) serves to swing the inner end of the lever (53) downwardly about the pivot trunnions (72) carried by the swinging link structure (73). During this movement or" the lever (63) the links (75) act through the pressure plate (80), springs (83), and arm (20) to press the riding roll (17) towards the main roll (16) and thereby serves to resist lifting of the riding roll by atmospheric pressure. The shoe ('78) which operates in the guide (79) controls the movement of the links (75) in a desirable manner. The slide (70) provides, in conjunction with the screw (71) for convenient adjustment of the pivot trunnions (72) to vary the throw of the lever (63). This adjustment of the trunnions ('72) enables the pressure applied to the riding roll (1'?) to be varied while the power exerted by the piston (65) remains constant.

The interposition of the springs (83) between .sociatedtherewith.

justments of the riding roll relative to the main roll is provided for without disturbing the efficiency of the seal.

The upper wall surface (28a) of the casting (28) is preferably curved along an arc concentric to the pivotal axis aiforded by the trunnions 58 and is disposed for sliding engagement with the correspondingly curved surface (88) of the cross member (89) which forms part of the end Wall of the vacuum chamber. Rubber sealing strips (90) are carried by the cross member (89) and arranged to prevent leakage of air between the surfaces (28a) and (88). The cross memher (89) is also preferably provided with suitable doors (91) to facilitate inspection and adjus ment of the upper labyrinth seal and parts asi In the foregoing I have described the complete assembly comprising what I now consider to'be the preferred embodiments of my invention, but it will be understood that-various modifications are contemplated within the scope and spirit of the appended-claims and thatvarious features of the complete assembly may possibly be used alone and in other combinations.

Having thus described my invention, what I claim is:

l. The combination of a vacuum chamber equipped with rolls between which sheet material is passed during its travel into or out of said chamber, a sealing member arranged adjacent to each 'roll and having its roll opposing surface grooved to retard the leakage of air across said surface and into the vacuum chamber, and movable supporting means mounting one of said rolls and its associated sealing member for unitary movement relative to the companion roll.

2. The combination of a vacuum chamber equipped with a main roll and a riding roll be-' tween which sheet material is passed during its travel into and out of said chamber, a sealing member arranged adjacent to each roll and having its roll opposing surface provided with a series of parallel longitudinally extending grooves-arranged to retard leakage of air across said surface and into the vacuum chamber, the riding roll and its associated seal member being connected to each other and movable as a unit relative to the main roll.

3. The combination of a vacuum chamber equipped with a pair of normally engaging rolls, a longitudinally extending sealing member positioned close to each roll, the roll opposing surface of said member being grooved to retard l akage of air thereacross, and supporting means mounting one of said rolls and its sealing member for unitary movement relative to the companion roll, said means including pressure applying devices controlled by the vacuum in said chamber and functioning to hold the movable roll to its corn- 1 panion roll and to resist displacement of the movable r011 by atmospheric pressure when a high vacuum is present in said chamber.

4. The combination with a vacuum chamber equipped with amain roll and a movable riding roll between which sheet material is passed during its travel into and out of said chamber, of a longitudinally extending sealing member positioned close to each roll, the roll opposing surface of said sealing member being grooved to retard leakage of air across said surface, a pair of swinging arms mounted at one end to swing about a horizontal axis, said arms having intermediate portions connected to and carrying the riding roll, and a support for the riding roll sealing member also mounted to move about said axis so that the relation between said riding roll and its sealing member remains unchanged during movement of the riding roll relative to the main roll.

5. The combination of a vacuum chamber equipped with a main roll and a movable riding roll between which sheet material is passed during its travel into or out of said member, movable supporting members carrying said riding roll and means co-acting with said supporting members to exert pressure on the riding roll in the direc-- tion of the main roll, said means comprising cylinders open at one end to the atmosphere and having their opposite ends communicating with the interior of the vacuum chamber, pistons operating in said cylinders and devices controlled by movement of said pistons for exerting pressure on the riding roll supporting members.

6. A structure as claimed in claim 5 in which the pressure applyin devices interposed between the pistons and the riding roll supporting members includes springs functioning to absorb shocks incident to the passage of wads of paper or similar solid bodies bet; een the rolls.

'7. The combination of a vacuum chamber equipped with a main roll and riding roll between which paper is passed during its travel into or out of said chamber, a sealing member associated with each roll and having its roll opposing surface grooved to retard leakage of air across said surface and into the vacuum chamber, movable supporting means for the riding roll arranged to provide for movement of said roll to and from the main roll, the sealing member associated with the riding roll being connected to and movable with said roll supporting means so that the relation between the riding roll and its sealing member remains unchanged during movement of the riding roll to or from the main roll, means for resiliently applying pressure on the riding roll in the direction of the main roll and means controlled by the degree of vacuum developed in the vacuum chamber for increasing or decreasing the pressure exerted on the riding roll by said pressure applying means.

8. The combination of a vacuum chamber equipped with a pair of sealing rolls between which sheet material is passed during its travel into or out of said chamber, a longitudinally extending sealing member associated with each roll and having its roll opposing surface provided with parallel longitudinally extending grooves,

stationary casting slidably supporting the sealing member associated with one of said rolls, a movable casting slidably supporting the sealing member associated with the remaining roll and movable supports for the last mentioned roll connected to the supporting casting of the associated sealing member so that the relation between said roll and sealing member remains unchanged during movement of the rollto or from the companion roll. g

9. The combination of a vacuum chamber equipped with a main roll and a riding roll between which sheet material passes during its travel into or out of said chamber, a longitudinally extending sealing member associated with each roll and having its roll opposing surfaces provided with spaced parallel grooves serving to retard leakage of air across said surface, a movable support for the riding roll sealing member having trunnions rotatably mounted in the side walls or" said chamber, a lever arm fixed at one end or" each of said trunnions and riding roll supports carried by said lever arms whereby the ridroll is mounted to move to or from the main roll without changing the relation between the riding roll and its associated sealing member.

19. The combination of a vacuum chamber equipped with a main roll and a riding roll between which sheet material is passed during its travel into or out of said chamber, a longitudinally extending sealing member associated with each roll and having its roll opposing surface provided with parallel longitudinally extending grooves servin to retard leakage of air across said surface, a movable pport for the riding roll sealing member having end trunnions rotatably journalled in the side walls of said chamber, a pair of lever arms fixed at one end to said trunnions, riding roll supports carried by said lever arms where y the riding roll is supported to move to or from main roll without changing the relation be :1 the riding roll and its associated sealing member and pressure applying means acting against said lever arms to yieldingly hold the riding roll engaged. with the main roll.

11. The construction claimed in claim 10 including means responsive to variations in the de gree of vacuum maintained in the vacuum chamber for varying the pressure exerted against the lever arms by said pressure applying means.

12 The combination of a vacuum chamber equipped with a main roll and a riding roll between which sheet material is passed during its travel into or out of said chamber, a longitudinally extending sealing member associated with each roll and having its roll opposing surface grooved to retard leakage of air cross said surface, a support for the riding roll sealing member having end trunnions rotatably mounted in the side walls of said chamber, lever arms fixed at one end of said trunnions, supports for the riding roll carried by said lever arms whereby the riding roll is mounted to move to and from the main roll without changing the relation between the riding roll and its associated sealing member, a cylinder having one end open to the atmosphere and the other end in communication with the interior of the vacuum chamber, a piston movable in said cylinder in response to variations in the degree of vacuum maintained said vacuum chamber and means controlled by said piston to apply a varying degree or pressure to one of said lever arms in a direction resisting movement of the riding roll away from the main roll.

13. The combination with a vacuum chamber equipped with an opening through which sheet material is passed during its travel into or out of said chamber of means for sealing said opening including a sealing roll, a lon itudinally extending sealing member associated with said roll and having its roll opposing surface grooved to retard leakage of air across said sunace, a support for said sealing member having end trunnions journalled in the side walls of said chamber, lever arms fixed to said trunnions and suporting bearings for said roll carried by said lever arms.

14.. The combination or" a vacuum chamber having anopening through which sheet material is passed during its travel into and out of said chamber, and means for sealing said opening including a main roll and a riding r011 normally resting on said main roll, movable supports for the riding r011 permitting said roll to move to'and from the main r011, pressure applying means engaging said supports f or resisting movement of the riding roll away from the main roll, pressure re- 

